1. Technical Field
The invention relates to a brightness controller for adjusting the brightness of an image on a display. In particular, the invention relates to a brightness control system for modifying the brightness of specific portions of an image.
2. Related Art
Both analog displays such as Cathode Ray Tubes (CRTs) and digital displays such as Liquid Crystal Displays (LCDs) create images from individual closely spaced points. Each point in the image is referred to as a picture element or pixel. The image data in the video data stream sent to the display conveys information which controls the brightness of each pixel.
In the past, dynamic changes to image brightness often required time consuming and computationally expensive brightness recalculations. This was particularly true when the recalculation of image data was done on a pixel-by-pixel basis. With the introduction and widespread use of high resolution displays, processing demands for dynamic brightness changes were often quite significant.
Displays are common components of vehicle navigation systems, entertainment systems, and game systems. A navigation system, for example, provides core functionality including the display of map location and route information to the driver. In addition to these core functions, the navigation system often provides extensive additional functionality for the driver. Thus, the processing demands on the navigation system (and other systems) are already significant, even without the added burden of dynamic image brightness control.
Therefore, a need exists for an improved brightness control system.